Long time no news. Sorry for that.
I'm still working almost every days on romcenter. The development is mostly refactoring. It will produce better code, more maintainable, testable and robust. I already added more than 50 automated tests.
I also fixed some random crashes occuring on multithreaded operations.

I worked on the filtering feature as well and rc4 can now identify games regions on most dat type, even if no regions data are available. This is the case for mame for example.

This part is almost finished. I will then fix reported bugs and the release will be ready.